This study compares two different brands of thyroxine (thyroid hormone). Currently, pharmacists may be substituting generic formulations of thyroid hormone without your doctor knowing about this. Although a small difference in thyroid function is not significant in most healthy children, adolescents and adults, in infants and toddlers even a small difference in thyroid function can have important harmful consequences on brain development. The purpose of the present study is to learn whether the difference between brands of thyroid hormone that are currently being substituted is sufficient to cause a difference in thyroid function.

Randomized crossover study using 8 weeks of one form of levothyroxine, then 8 weeks of the other form of levothyroxine. The dose of medication does not change throughout the duration of the study.

Other Names:

Levothyroxine (manufactured by Sandoz)

Synthroid (manufactured by Abbott)

Detailed Description:

This study is an unblinded, randomized controlled cross-over study, which involves taking 2 different forms of levothyroxine sequentially over a 16 week period. Subjects will have a total of 3 visits over this time period. At the first visit, subjects are randomized to receive either generic (Sandoz) levothyroxine or Synthroid (Abbott) brand of levothyroxine. Blood is drawn for baseline thyroid function studies and other markers which are influenced by thyroid hormone at each visit. The second visit is the cross-over visit, and the final visit is a close-out visit, after which each subject will resume taking their previous formulation of levothyroxine.

Eligibility

Ages Eligible for Study:

3 Years to 18 Years

Genders Eligible for Study:

Both

Accepts Healthy Volunteers:

Yes

Criteria

Inclusion Criteria:

Age between 3 and 18 years

Diagnosis of Congenital Hypothyroidism with initial TSH > 100

Ability to understand directions and follow all instructions

Exclusion Criteria:

Not on any drug interfering with absorption of levothyroxine

Contacts and Locations

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study.
To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below.
For general information, see Learn About Clinical Studies.

Please refer to this study by its ClinicalTrials.gov identifier: NCT00403390